The role of FDG PET in the management of lymphoma: what is the evidence base?

[18F]Fluorodeoxyglucose positron emission tomography (18F-FDG PET) is playing an increasing role in the management of both Hodgkin and non-Hodgkin lymphoma, offering potential advantages in the accuracy of disease assessment at a number of points in the management pathway. This review evaluates the current level of confidence in the use of PET technology in (1) initial staging, (2) the assessment of early response to chemotherapy, (3) the assessment of residual masses at completion of initial treatment, (4) follow-up, and (5) radiotherapy planning.     

The sternoclavicular joint: can imaging differentiate infection from degenerative change?

Objective  

The purpose of this study was to determine if there are imaging and clinical findings that can differentiate a septic sternoclavicular joint from a degenerative one.     

Brain metastases after stereotactic radiosurgery using the Leksell gamma knife: can FDG PET help to differentiate radionecrosis from tumour progression?

Stereotactic radiosurgery (SRS) using the Leksell gamma knife promotes acute and chronic local changes in glucose metabolism. We have been able to find very few papers on Medline on the subject of assessment of metastases by 2-[(18)F]fluoro-2-deoxy- D-glucose positron emission tomography (FDG PET) after SRS. The aim of this work was to specify the additional value of FDG PET, in comparison with magnetic resonance imaging (MRI), in differentiating SRS-induced radionecrosis from viable brain metastasis in a clinical setting. Fifty-seven metastases in 25 patients were treated by SRS. An average of 33 weeks later, all the patients underwent FDG PET. At the same time (SD=2 weeks) all the patients underwent MRI. The sensitivity, specificity and accuracy of both FDG PET and MRI examinations were calculated with reference to clinical and radiological follow-up or biopsies. The additional value derived from use of FDG PET after MRI was assessed and progression-free survival rates were compared. The difference in progression-free survival rates between the negative and positive subgroups was significant ( P=0.0005) for MRI and even more so ( P<0.00001) for FDG PET. Sensitivity, specificity and accuracy were 75% (6/8), 93.9% (46/49) and 91.2% (52/57) for FDG PET, and 100% (8/8), 65.3% (32/49) and 70.2% (40/57) for MRI. In the subgroup of patients with positive or non-diagnostic MRI, the probability of presence of a viable tumour was only 32% (8/25). This probability increased to 100% (5/5) when subsequent FDG PET was positive and decreased to 11.1% (2/18) when FDG PET was negative. The frequency of a viable neoplasm was significantly different ( P=0.001) in the FDG PET negative and positive subgroups. MRI and FDG PET both have an important predictive value for persistent viable metastases after treatment by SRS. Neither sensitive but non-specific MRI nor specific but insensitive FDG PET is reliable on its own. While FDG PET significantly improved the diagnostic accuracy in the subgroup of patients with positive and non-diagnostic MRI, it provided no additional value in the MRI-negative subgroup.     

Comparison of [18 F]FDG PET/CT and MRI in the diagnosis of active osteomyelitis

Objective

In diagnosing osteomyelitis (OM) both MRI and [18 F]FDG PET-CT proved to be accurate modalities. In anticipation of the advent of hybrid PET/MRI scanners we analyzed our patient group to give direction to future imaging strategies in patients with suspected OM.

Materials and methods

In this retrospective study all patients of a tertiary referral center who underwent both an MRI and a PET for the diagnosis of OM were included. The results of those scans were evaluated using patient’s histology, microbiological findings, and clinical/radiological follow-up. Additionally, ROC curve analysis of the SUVmax and the SUVmax ratio on the PET scans was performed. Two imaging strategies were simulated: first MRI followed by PET, or vice versa.

Results

Twenty-seven localizations in 26 patients were included. Both MRI and PET were shown to be accurate in our patients for the qualitative detection of OM. A cut-off value for the SUVmax of 3 gave optimal results (a specificity of 90 % with a sensitivity of 88 %). The SUVmax ratio gave a worse performance. The two simulated imaging strategies showed no difference in the final diagnosis in 20 out of 27 cases. Remarkably, 6 equivocal cases were all correctly diagnosed by the second modality, i.e., PET or MRI.

Conclusion

Both MRI and [18 F]FDG PET were accurate in diagnosing OM in a tertiary referral hospital population. Simulation of imaging strategies showed that a combined sequential strategy was optimal. It seems preferable to use MRI as a primary imaging tool for uncomplicated unifocal cases, whereas in cases with (possible) multifocal disease or a contraindication for MRI, PET is preferred. This combined sequential strategy looks promising, but needs to be confirmed in a larger prospective study.     

Cancer of unknown primary origin: Can FDG PET/CT have a role in detecting the site of primary?

Objectives

Our aim in this study was to evaluate the efficiency of combined positron emission tomography and computed tomography (PET/CT), in the detection of the primary tumor origin in patients with cancer of unknown primary (CUP).

Chest ultrasound in the assessment of patients in ICU: How can it help?

Background: Different imaging techniques can be used for assessment of chest problems in ICU patients, however ultrasound is a good diagnostic tool giving more information and at the same time without exposure to radiation and without risk of critical patient transfer.Aim of the work: The aim of this work was to study the role of thoracic ultrasound in assessment of ICU patients.Materials and methods: The study was carried out on 30 patients admitted to the ICU.B and M modes chest ultrasound was done for all patients using EsaoteMyLab?Alpha with eHD Technology.Results: The study included 19 males and 11 females with mean age of 42.6 ± 21.4 years. In this study ultrasound was able to diagnose Pneumothorax: 3 cases (10%). Pleural effusion: 20 cases (66.6%). Alveolar interstitial syndrome: 7 cases (23.3%). Lung consolidation: 20 cases (66.6%). Pulmonary infarcts: 1 case (3.3%). Neoplastic disease: 1 case (3.3%). Chest wall pathology: 1 case (3.3%).Conclusion: Ultrasound examination of the chest is a non- invasive, and promising bed side tool for examination of ICU patients.     

Three tesla magnetic resonance imaging of the anterior cruciate ligament of the knee: can we differentiate complete from partial tears?

Purpose  

To determine the ability of 3.0T magnetic resonance (MR) imaging to identify partial tears of the anterior cruciate ligament (ACL) and to allow distinction of complete from partial ACL tears.     

Clinical value of FDG PET/CT in the diagnosis of suspected recurrent ovarian cancer: is there an impact of FDG PET/CT on patient management?

Purpose  

The aim of this study was to evaluate the clinical value of FDG PET/CT in patients with suspected ovarian cancer recurrence as compared with diagnostic CT, and to assess the impact of the results of FDG PET/CT on treatment planning.     

Which kinds of lymph node metastases can FDG PET detect? A clinical study in melanoma.

The purposes of this study were to establish the diagnostic accuracy of FDG PET for lymph node metastases and to determine the smallest detectable volume of disease. METHODS: Using FDG PET, we preoperatively studied 56 lymph node basins in 38 patients with a clinical or instrumental diagnosis of lymph node metastases from melanoma. All lymph node basins underwent node dissection. The FDG PET results were compared with the postoperative histopathology results. PET images were obtained using a GE 4096 WB scanner, after injection of a mean activity of 496 MBq (range, 366-699 MBq) of FDG. RESULTS: The efficacy of FDG PET in the diagnosis of involved lymph node basins was good. Sensitivity was 95% (35/37); specificity, 84% (16/19); accuracy, 91% (51/56); positive predictive value, 92% (35/38); and negative predicative value, 89% (16/18). Metastases were shown histologically in 114 of 647 surgically removed lymph nodes. FDG PET detected 100% of metastases > or = 10 mm, 83% of metastases 6-10 mm, and 23% of metastases < or = 5 mm. Moreover, FDG PET had high sensitivity (> or = 93%) only for metastases with more than 50% lymph node involvement or with capsular infiltration. CONCLUSION: Our study shows that FDG PET has a reasonable sensitivity and specificity for detecting the presence or absence of lymph node metastases in patients with melanoma. However, even if able to detect small volumes of subclinical macroscopic disease, FDG PET cannot detect subclinical microscopic disease with acceptable sensitivity. The specificity of FDG PET is good, but some false-positive results may occur.